I wondered whether the good folks at Nolo had lost it when they proposed in the mid-1990’s that I write a book about criminal law and processes. Nolo was the leading self-help law book publisher, and very few criminal defendants represent themselves. This is almost always a good thing, and a book trying to expand the population of pro se defendants would have done more harm than good.

So how did I (along with my co-author and former student Sara Berman) come to write The Criminal Law Handbook, which in Nolo’s 40th year will reach its 12th edition? My imagined reader was not a pro se defendant but rather an educated client. Lawyers and clients are supposed to work as a team, and clients are supposed to decide whether to plead guilty, remain silent at trial or testify, ask for a jury trial and make many other important life-affecting decisions. Most criminal defendants, I realized, are so scared and so unaware of their rights and obligations in the criminal justice process that they have little choice but to follow legal advice that they barely comprehend. Thus, the book’s purpose has been from the outset to empower criminal defendants to participate meaningfully in decisions affecting their future.

At the same time, defendants are not the only consumers of criminal justice. In a democracy, criminal justice is a public good that must also serve the interests of crime victims, witnesses, family members and society as a whole. And if there’s life on Mars, then Martians probably need a top-notch criminal justice system too. So that’s when I realized that the good folks at Nolo are pretty smart after all.

It’s fair to say that the human motivations and social conditions that lead to crime haven’t changed much in the last 40 years, and probably not in the last 40 centuries. What has changed radically are the instrumentalities for committing crimes and the technology for solving them. The internet, to take an obvious example, is a remarkable tool for communication and research. To those bent on crime, however, the internet is a launching pad for identity theft, sexual predation and consumer scams too numerous to describe. If Sir Isaac Newton were around today, he might have written a new law of motion along the lines of “Every technological advance produces an equal and opposite advance in its use as a means of crime.”

DNA analysis may be the technological equivalent of the internet on the crime solving front. DNA analysis has enabled the police to solve even decades-old crimes, bringing some measure of relief to crime victims and their families even if culprits are beyond the law’s reach. Yet DNA analysis has also exposed weaknesses in the criminal justice system. DNA analysis has demonstrated that many prisoners who have been behind bars for years were actually innocent. In most of these cases, the error was the result of eyewitnesses swearing earnestly but mistakenly that “there’s no doubt in my mind that the defendant committed the crime.”

Human beings created and develop the criminal justice system, guaranteeing its imperfection. We can try to make it at least one grain of sand better each day, and to that end The Criminal Law Handbook and the forthcoming Criminal Law Desk Reference are devoted.